Typically double-posting is frowned upon at MR, though they definitely need a way to cross-post questions like this to multiple forums. I downloaded the PDF sample you posted in the other thread and looked at it. There are definitely no spaces in the OCR layer (see excerpt from decompressed PDF stream below), so it's a mystery as to why they are put in by Amazon's conversion.
Code:
...
0.05 Tc 9.4807 0 0 9.1 63.27 418.57 Tm
(der )Tj
9.2469 0 0 9.1 79.35 418.57 Tm
(Ganzheitsworte )Tj
9.65 0 0 9.1 146.38 418.57 Tm
(mag )Tj
/Suspect <</Conf 0 >>BDC
9.1849 0 0 9.1 167.15 418.57 Tm
(salom )Tj
...